IfTokenParser.php

<?php


/*
 * This file is part of Twig.
 *
 * (c) Fabien Potencier
 * (c) Armin Ronacher
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Twig\TokenParser;

use Twig\Error\SyntaxError;
use Twig\Node\IfNode;
use Twig\Node\Node;
use Twig\Node\Nodes;
use Twig\Token;

/**
 * Tests a condition.
 *
 *   {% if users %}
 *    <ul>
 *      {% for user in users %}
 *        <li>{{ user.username|e }}</li>
 *      {% endfor %}
 *    </ul>
 *   {% endif %}
 *
 * @internal
 */
final class IfTokenParser extends AbstractTokenParser {
    public function parse(Token $token) : Node {
        $lineno = $token->getLine();
        $expr = $this->parser
            ->getExpressionParser()
            ->parseExpression();
        $stream = $this->parser
            ->getStream();
        $stream->expect(Token::BLOCK_END_TYPE);
        $body = $this->parser
            ->subparse([
            $this,
            'decideIfFork',
        ]);
        $tests = [
            $expr,
            $body,
        ];
        $else = null;
        $end = false;
        while (!$end) {
            switch ($stream->next()
                ->getValue()) {
                case 'else':
                    $stream->expect(Token::BLOCK_END_TYPE);
                    $else = $this->parser
                        ->subparse([
                        $this,
                        'decideIfEnd',
                    ]);
                    break;
                case 'elseif':
                    $expr = $this->parser
                        ->getExpressionParser()
                        ->parseExpression();
                    $stream->expect(Token::BLOCK_END_TYPE);
                    $body = $this->parser
                        ->subparse([
                        $this,
                        'decideIfFork',
                    ]);
                    $tests[] = $expr;
                    $tests[] = $body;
                    break;
                case 'endif':
                    $end = true;
                    break;
                default:
                    throw new SyntaxError(\sprintf('Unexpected end of template. Twig was looking for the following tags "else", "elseif", or "endif" to close the "if" block started at line %d).', $lineno), $stream->getCurrent()
                        ->getLine(), $stream->getSourceContext());
            }
        }
        $stream->expect(Token::BLOCK_END_TYPE);
        return new IfNode(new Nodes($tests), $else, $lineno);
    }
    public function decideIfFork(Token $token) : bool {
        return $token->test([
            'elseif',
            'else',
            'endif',
        ]);
    }
    public function decideIfEnd(Token $token) : bool {
        return $token->test([
            'endif',
        ]);
    }
    public function getTag() : string {
        return 'if';
    }

}